Invisible zip fastener slider and garment having such a fastener

ABSTRACT

A garment has: a pair of fabric panels each connected to a zip tape; the zip tape including a pair of rows of zip teeth; a zip slider, having a bridge extending upwardly and a pull tab connected to the bridge via an intermediate link; the zip slider being movable along the zip tape to interdigitate the rows of zip teeth by pulling of the pull tab; the panels provide a pair of lips extending over the zip teeth thereby to cover the slider; the intermediate link, pull tab and bridge are constructed so that rotation of the pull tab causes the intermediate link to bear against outer surfaces of the bridge.

BACKGROUND TO THE INVENTION

1. Field of the Invention

The present invention relates to a garment having a zip fastener and to a zip slider for use in a garment having such a zip fastener. In addition, the present invention relates to garments such as ladies' dresses, where it is desired, as much as possible, to conceal the zip fastener and to a zip slider of a kind known as an ‘invisible’ slider typically used on garments where the slider is desirably concealed.

2. Description of Related Art

Invisible sliders are known per se. For example, GB1377451 discloses embodiments of such a slider. The slider has a body adapted to slide longitudinally along opposing pairs of zip teeth attached to a stringer tape. As the slider moves along the tape, separate rows of zip teeth on the tape enter into distinct entry channels located at the front of the body. Movement of the slider feeds the rows of teeth into a single, mating channel at the rear of the body, where the teeth are forced to interdigitate, which knits the rows of teeth together—and thereby fastens the zip; pulling the body in the reverse direction reverses the process and unfastens the zip. The slider is pulled along the tape by a pull-tab, which is connected to the body at bridge which extends upwardly from the body. Typically, in the case of an invisible slider, the pull tab is connected to the bridge via an intermediate link. This facilitates easy articulation of the pull tab relative to the body and also enables the pull tab to have smaller dimensions. In order to conform to the requirements of a small, discreet and concealed zip and slider, the bridge, the pull tab and the intermediate link are necessarily of a more flimsy construction that is typically the case in connection with a slider that is not intended to be concealed.

A problem associated with such a construction is that comparatively little twisting force is required in order to break the connection of the pull tab to the slider body. This is potentially dangerous where such a slider is to be used, for example, on childrens' clothing since ingestion of the pull tab with the attendant possibility of choking may then occur.

SUMMARY OF THE INVENTION

One aspect of the present invention lies in an appreciation of the intrinsic ability of a slider of such a construction to be made to a stronger specification than previously thought possible.

The present invention provides an alternative form of invisible slider which ameliorates the above-mentioned difficulties.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way of example, and with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a zip slider according to an embodiment of the present invention;

FIG. 2 is a section on II-II in FIG. 1;

FIG. 3 is a section on in FIG. 1;

FIG. 4 is a section on IV-IV in FIG. 3.

FIG. 5 is a section through a zip slider, located upon a zip tape which is part of a garment;

FIG. 6 is plan view of a spring member; and

FIG. 7 is a plan view of the interconnecting link shown in FIGS. 1 and 2.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring now to FIGS. 1 to 4, an invisible slider for a zip fastener used for used in garments where ‘invisible’ zips are desired, comprises a slider body which is movable longitudinally relative to opposing rows of teeth 30 attached to a stringer tape 32. The body has upper and lower interconnected elements 10, 20 configured to provide a pair of entry channels 22, 24 through which the separate rows of teeth 30 are fed as the slider moves relative to the tape 32. The entry channels feed to mating channel 28 where the teeth of the two rows are forced into inter-digitation in a manner well-known per se thereby to fasten the zip. The slider body additionally comprises a bridge 60 which projects upwardly from the upper element 20 of the body. A pull tab 70, by means of which the slider is pulled along the zip tape is connected to the bridge 60 via an intermediate link 80.

The bridge 60 is formed of forward and rearward posts 60A, B whose longitudinal spacing defines a cleft 66 between them. Referring additionally to FIG. 5, a longitudinal slot 68 within the forward and rearward bridge posts 60A, B accommodates a spring member 100. In the present embodiment the member 100 is a bar spring and its configuration is shown in more detail in FIG. 6. The bar spring member 100 comprises, at one end, a locking prong 110. The locking prong 110 projects through an aperture 120 in the upper element 20 and into the mating channel 28, enabling the locking prong 110 to bear against the interdigitated zip teeth and thereby lock the position of the slider body relative to the zip. A retaining member, here having the form of a retaining bar 140 is located at the other end of the bar spring member 100, i.e. the end distal from the locking prong 110. The locking prong 110 and retaining member 140 are interconnected by a biasing loop 130 which reacts resiliently against the retaining bar 140 and thereby serves to urge the locking prong 110 into the mating channel 28 to lock the zip in position.

The intermediate link 80, shown in detail in plan view in FIG. 7, is held in the cleft 66 underneath the locking prong 110 in a manner enabling the link 80 to pivot relative to the body about transverse axes (i.e. extending transverse to the longitudinal direction of slider motion relative to the zip teeth). Such pivoting is, in the present embodiment, enabled by sufficient clearance in the cleft and ‘give’ in the retaining bar and typically takes place under the influence of a pulling force applied to the pull tab 70. As a consequence of this configuration, the link 80 is effectively prevented from being pulled free of the bridge 60 by both the locking prong 110 and the retaining bar 140. When the pull tab is used to urge the slider body in the forward direction, the link pivots bears against a ramp 150 on the outside of the forward bridge part 60A. The angle of the ramp 150 is such that the intermediate link 80 will adopt an attitude whereby any pulling force applied to the pull tab 70 will operate both longitudinally and upwardly. Thus, a forward pulling force in on the pull tab 70 acts to cause the intermediate link to provide a forward and upward force to the locking prong 110, acting to lift the locking prong 110 clear of its engagement with the zip teeth and thereby facilitating the forward motion of the slider along the zip. Conversely, when the pull tab 70 is operated to pull the slider rearwardly, the intermediate link then bears against the angled under surface 160 of the locking prong 110 which reacts to create an upward force on the locking prong 110, once again to disengage it from the zip teeth and thereby enable relative motion of the slider and zip teeth.

Referring now additionally to FIG. 5, the slider is typically employed as a closure in a garment 200. The garment comprises panels 250 of fabric which are attached to the zip tape 32 by a seam 252. The nature of the garment is such that it is desirable to conceal both the zip teeth and the body of the slider. Accordingly, the garment is constructed with a lip 254 on each panel 250, which extends beyond the seam 252 and over the knitted zip teeth 50 (when the zip is closed). In FIG. 5 the garment is illustrated with the lips protruding upwardly to accommodate the passage of the slider body and it will be appreciated that, even in this position, the slider body is concealed to a degree.

The relatively refined construction of the pull tab 70 is such, therefore, as to provide a relatively discreet ‘handle’ via which to pull the slider body, and as a consequence, the lips of the fabric panels do not have to open too far to accommodate the pull tab 70, which servers thereby to retain the ‘invisible’ characteristics of the slider within the garment 200.

To ameliorate difficulties arising in connection with the aforementioned problems whereby invisible sliders are susceptible to relatively easy breakage such that the pull tab may easily be detached from the slider, the present embodiment has a construction which withstands a minimum torque applied to it of 4 inch lbs (equivalent force) and a minimum tension in both longitudinal (i.e. forward and rearward) and perpendicular (i.e. orthogonal to the direction in which the zip tape 32 extends) force of 15 lbs (equivalent force).

Design features of the present invention that provide such robustness include the relative dimensions and fit of the external geometry bridge 60 and the intermediate link 80. These are such as to provide that, rotational force applied to the link 80 about a longitudinal axis causes the link 80 to bear against the outside of the bridge 60 so that little or no rotational force is borne by the bar spring. Thus, in one embodiment, the internal loop 300 of the intermediate link which accommodates pivoting of the link 80 relative to the bridge 60 so that the link can straddle the forward part 60A when the slider is pulled forward along the zip tape and straddles the rear part 60B when the slider is pulled rearwardly along the tape 32, has a width W of 2.1 mm, while the link has a thickness of 0.8 mm. The width of the bridge is 1.65 mm and the height of the bridge 60 is 4 mm. Accordingly, rotation of the link will cause it to bear against the bridge providing greater inherent strength. In addition, when the intermediate link is in an upright position, i.e. extending perpendicularly upward from the body, rotation of the pull tab will cause it to bear against the inner surfaces of the cleft 66 between the front and rear parts 66A, B of the bridge 60. Further, in perpendicular tension, it will be noted that the intermediate link 80 bears against the locking prong 110 which, by virtue of the force applied by the biasing loop 130, restricts its upward motion but, in addition that motion is also restricted by the retaining bar 140 which acts serially with the locking prong to resist motion of the intermediate link 80 arising as a consequence of perpendicular tension. 

1. A zip slider comprising: a body adapted to move longitudinally in a first direction along opposing rows of tip teeth to interdigitate or extradigitate the teeth and fasten or unfasten the zip; a bridge extending upwardly from the body and comprising forward and rearward longitudinally-spaced posts defining a cleft therebetween; a pull tab, connected to the bridge by an intermediate link retained in the cleft for pivotal motion relative to the body about a transverse axis; an elongate spring member having a locking prong and a retaining bar interconnected by a biasing loop which urges the locking prong against interdigitated teeth; wherein the external dimension of the bridge and the configuration of the intermediate link are such that, when the pull tab is rotated about a longitudinal axis, the intermediate link bears against the outside of the bridge.
 2. (canceled)
 3. A zip slider according to claim 1 wherein the pull tab is able to withstand at least a torque of 4 in lbs equivalent force.
 4. A garment having a zip slider according to claim
 1. 5. A garment according to claim 4 having: a pair of fabric panels each connected to a zip tape along with the zip slider is movable to interdigitate the rows of zip teeth by pulling of the pull tab; the panels providing a pair of lips extending over the zip teeth thereby to cover the slider; the intermediate link, pull tab and bridge are constructed so that rotation of the pull tab causes the intermediate link to bear against outer surfaces of the bridge.
 6. A zip slider according to claim 1 wherein when the intermediate link is in an upright position extending substantially orthogonal to the longitudinal axis, rotation of the pull tab about an upright axis causes the intermediate link to bear against inwardly-facing surfaces of the cleft. 